1. Field of the Invention
The present invent on relates generally to fire fighting systems for use in fighting and extinguishing hydrocarbon and other flammable liquid fires. More particularly, the present invention relates to a foam free test system for the environmentally safe testing the foam delivery systems used on Aircraft Rescue and Fire Fighting (ARFF) vehicles.
2. Description of the Prior Art
Currently, fire fighting guidelines and policies require quarterly and annual Aqueous Film Forming Foam (AFFF) discharge tests on all Aircraft Rescue and Fire Fighting (ARFF) vehicles. The foam discharge test verifies that the on-board foam delivery system is functioning properly, thereby ensuring a vehicle""s fire fighting equipment is operational when called upon to save lives and property.
The method presently in use for determining fire fighting vehicle performance in the field is to discharge foam through each of the vehicle""s nozzles and then collect foam samples in accordance with the National Fire Protection Association (NFPA) 412 Standard for Evaluating Aircraft; Rescue and Fire Fighting Foam Equipment. Each vehicle is equipped with at least two and up to five different types of nozzles, depending on the vehicle type. This procedure generates large amounts of AFFF wastewater. Depending on the type of vehicle, the generated AFFF wastewater volume may be anywhere from 850 gallons to more than 2,600 gallons per vehicle for each 30-second nozzle foam discharge test. This includes flushing the system with water as required under the guidelines of NFPA 412. At present, the Department of Defense (DOD) agencies have more than 1,200 ARFF vehicles in the fire fighting arsenal inventory at more than 240 activities. The net result is the testing of fire fighting vehicles generates a substantial amount of AFFF wastewater annually.
Fire fighting personnel often conduct routine daily, weekly or monthly AFFF discharge testing, in addition to the mandated requirements, due to low confidence in the performance of the fire fighting vehicle""s foam delivery system. The routine testing is a visual check of foam being emitted through the various nozzles of the vehicle. It is estimated that a minimum of 5 seconds is required for the fire fighter to verify that foam is being emitted through a single nozzle. Depending on the type of vehicle, these 5 second routine checks, with system flush, generates 500 to 1,500 gallons of AFFF wastewater per ARFF vehicle. These routine foam delivery system tests generate significant amounts of AFFF wastewater, which result in environmental damage.
Despite its wide use and effectiveness for fire fighting, AFFF poses an environmental problem because of its resistance to biodegradation, its toxicity due to constituents butyl carbitol (a glycol ether) and perfluorooctyl sulfonates (PFOS), its high biochemical oxygen demand (BOD), and its chemical oxygen demand (COD).
In addition to the environmental concerns with respect to AFFF wastewater discharges into the environment, the significant foaming capacity of AFFF makes the recovery and treatment of spent AFFF very difficult. In some regions, the military is no longer allowed to discharge AFFF wastewater to industrial waste treatment plant facilities because of subsequent treatment plant fouling and damage. Hence, when disposing of AFFF wastewater, the military incurs additional cost associated with hazardous waste handling, collection, disposal, and issues relating to liability for environmental and other damage.
The NoFoam system for testing the foam delivery system on a fire fighting vehicle comprises a control panel having a flow meter, flow sensor piping and valves, and a holding tank for the surrogate fluid mounted on a portable trailer/stationary-pad. The fire fighter simply drives the vehicle to be tested to the .mobile/stationary pad NoFoam system and connects to the delivery system""s fluid supply line. At this point, the user continues through the fire fighting foam discharge procedures. A flow meter installed in the NoFoam system senses the flow rate of the surrogate fluid and allows the user to read a display for the flow meter. The firefighter simply reads the monitor and quickly determines the vehicle""s foam delivery system performance. The flow that is monitored represents the flow rate of the AFFF concentrate into the vehicle""s AFFF delivery system. The use of a dye-water solution allows the user to visually inspect the vehicle""s performance, although the NoFoam system still performs adequately without the dye concentrate. The dye concentrate selected is an environmentally benign, biodegradable dye, certified by the National Sanitation Foundation (NSF) International to NSF Standard 60 for the use in potable water (Drinking Water Treatment Chemicals Health Effects), and DOD adopted industry standard issued by the American National Standard Institute.